hanzoai_agent/sdk/go/client/client.go

package client

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"path"
	"strings"
	"time"

	"github.com/hanzoai/agents/sdk/go/types"
)

// Client provides a thin wrapper over the HanzoAgents control plane REST API.
type Client struct {
	baseURL    *url.URL
	httpClient *http.Client
	token      string
	apiKey     string
}

// Option mutates Client configuration.
type Option func(*Client)

// WithHTTPClient allows custom HTTP transport configuration.
func WithHTTPClient(h *http.Client) Option {
	return func(c *Client) {
		if h != nil {
			c.httpClient = h
		}
	}
}

// WithBearerToken sets the Authorization header for each request.
func WithBearerToken(token string) Option {
	return func(c *Client) {
		c.token = token
	}
}

// WithAPIKey sets the X-API-Key header for each request.
func WithAPIKey(key string) Option {
	return func(c *Client) {
		c.apiKey = key
	}
}

// New creates a new Client instance.
func New(baseURL string, opts ...Option) (*Client, error) {
	if baseURL == "" {
		return nil, fmt.Errorf("baseURL is required")
	}

	parsed, err := url.Parse(strings.TrimSuffix(baseURL, "/"))
	if err != nil {
		return nil, fmt.Errorf("invalid baseURL: %w", err)
	}

	c := &Client{
		baseURL: parsed,
		httpClient: &http.Client{
			Timeout: 10 * time.Second,
		},
	}

	for _, opt := range opts {
		opt(c)
	}

	return c, nil
}

// RegisterNode registers or updates the agent node with the control plane.
func (c *Client) RegisterNode(ctx context.Context, payload types.NodeRegistrationRequest) (*types.NodeRegistrationResponse, error) {
	payload.LastHeartbeat = payload.LastHeartbeat.UTC()
	payload.RegisteredAt = payload.RegisteredAt.UTC()

	var resp types.NodeRegistrationResponse
	if err := c.do(ctx, http.MethodPost, "/api/v1/nodes", payload, &resp); err != nil {
		if apiErr, ok := err.(*APIError); ok && apiErr.StatusCode == http.StatusNotFound {
			// Fallback to legacy registration endpoint for older servers.
			if fallbackErr := c.do(ctx, http.MethodPost, "/api/v1/nodes/register", payload, &resp); fallbackErr != nil {
				return nil, fallbackErr
			}
			return &resp, nil
		}
		return nil, err
	}
	return &resp, nil
}

// UpdateStatus renews the node lease and optionally reports lifecycle changes.
func (c *Client) UpdateStatus(ctx context.Context, nodeID string, payload types.NodeStatusUpdate) (*types.LeaseResponse, error) {
	var resp types.LeaseResponse
	route := fmt.Sprintf("/api/v1/nodes/%s/status", url.PathEscape(nodeID))
	if err := c.do(ctx, http.MethodPatch, route, payload, &resp); err != nil {
		if apiErr, ok := err.(*APIError); ok && apiErr.StatusCode == http.StatusNotFound {
			return c.legacyHeartbeat(ctx, nodeID, payload)
		}
		return nil, err
	}
	return &resp, nil
}

// AcknowledgeAction notifies the control plane that a pushed action completed.
func (c *Client) AcknowledgeAction(ctx context.Context, nodeID string, payload types.ActionAckRequest) (*types.LeaseResponse, error) {
	var resp types.LeaseResponse
	route := fmt.Sprintf("/api/v1/nodes/%s/actions/ack", url.PathEscape(nodeID))
	if err := c.do(ctx, http.MethodPost, route, payload, &resp); err != nil {
		return nil, err
	}
	return &resp, nil
}

// Shutdown informs the control plane that the node is shutting down gracefully.
func (c *Client) Shutdown(ctx context.Context, nodeID string, payload types.ShutdownRequest) (*types.LeaseResponse, error) {
	var resp types.LeaseResponse
	route := fmt.Sprintf("/api/v1/nodes/%s/shutdown", url.PathEscape(nodeID))
	if err := c.do(ctx, http.MethodPost, route, payload, &resp); err != nil {
		return nil, err
	}
	return &resp, nil
}

func (c *Client) do(ctx context.Context, method string, endpoint string, body any, out any) error {
	u := *c.baseURL
	rel := strings.TrimPrefix(endpoint, "/")
	basePath := strings.TrimSuffix(c.baseURL.Path, "/")
	if basePath == "" {
		u.Path = "/" + rel
	} else {
		u.Path = path.Join(basePath, rel)
		if !strings.HasPrefix(u.Path, "/") {
			u.Path = "/" + u.Path
		}
	}

	var buf io.ReadWriter = &bytes.Buffer{}
	if body != nil {
		if err := json.NewEncoder(buf).Encode(body); err != nil {
			return fmt.Errorf("encode request: %w", err)
		}
	}

	req, err := http.NewRequestWithContext(ctx, method, u.String(), buf)
	if err != nil {
		return fmt.Errorf("new request: %w", err)
	}

	if body != nil {
		req.Header.Set("Content-Type", "application/json")
	}
	req.Header.Set("Accept", "application/json")

	if c.token != "" {
		req.Header.Set("Authorization", "Bearer "+c.token)
	}
	if c.apiKey != "" {
		req.Header.Set("X-API-Key", c.apiKey)
	}

	resp, err := c.httpClient.Do(req)
	if err != nil {
		return fmt.Errorf("perform request: %w", err)
	}
	defer resp.Body.Close()

	respBody, err := io.ReadAll(resp.Body)
	if err != nil {
		return fmt.Errorf("read response: %w", err)
	}

	if resp.StatusCode >= 400 {
		return &APIError{
			StatusCode: resp.StatusCode,
			Body:       respBody,
		}
	}

	if out == nil || len(respBody) == 0 {
		return nil
	}

	if err := json.Unmarshal(respBody, out); err != nil {
		return fmt.Errorf("decode response: %w", err)
	}

	return nil
}

func (c *Client) legacyHeartbeat(ctx context.Context, nodeID string, payload types.NodeStatusUpdate) (*types.LeaseResponse, error) {
	route := fmt.Sprintf("/api/v1/nodes/%s/heartbeat", url.PathEscape(nodeID))
	if err := c.do(ctx, http.MethodPost, route, payload, nil); err != nil {
		return nil, err
	}
	lease := 120 * time.Second
	return &types.LeaseResponse{
		LeaseSeconds:     int(lease.Seconds()),
		NextLeaseRenewal: time.Now().Add(lease).UTC().Format(time.RFC3339),
	}, nil
}

// APIError captures non-success responses from the HanzoAgents API.
type APIError struct {
	StatusCode int
	Body       []byte
}

func (e *APIError) Error() string {
	return fmt.Sprintf("hanzo-agents api error (%d): %s", e.StatusCode, strings.TrimSpace(string(e.Body)))
}